The Concerto, the newest amp from Meier Audio, is essentially equivalent to the top Meier, the Symphony, with a less features and a few tweaks. As such, it employs Meier’s Active Balanced Ground topology, and includes his famous Crossfeed image enhancer (which is supposed to be improved from the Symphony, and as always is defeatable), and a gain switch. That’s it for “features” – one input, one SE output. There is, however, also a new volume pot, which Jan described as a discrete volume control with a total of 64 positions (versus 32 steps on the SYMPHONY) and with typical step-size being around 0.7 dB.

One other change - Instead of the use of the LM6171 op-amp in the SYMPHONY, the CONCERTO uses AD797 opamps. This is generally regarded as being an excellent sounding op-amp, from what I have read. Apparently the AD797 is extremely sensitive to the quality of the power supply, and Meier claims to have paid a lot of close attention to power supply design, including the use of a total of 85,000 uF of filter capacitance – which is a LOT. I personally really like home amps to have their PS onboard, and the Concerto indeed does.

Here is the chassis:

Not much around back - just two nice chassis-mounted RCA jacks, and an IEC power connector cable.

Jan has done a lot of work to make his amps quiet. I certainly heard the Concerto as being very quiet, and having a deep black background, which is a very important trait for a good amp, IMO. And Jan's work is backed up by specs - the Concerto has an almost impossible-sounding worst case S/N ratio of 117db (the graph indicates that noise is down by a minimum of -117db, and generally closer to -135db!). This is impressive:

Testing Methodology:

Headphones used in testing were the Beyerdynamic T1, DT880/600, DT990/600, HifiMan HE-5, JVC DX1000, and Shure SRH840. Sources were the Music Hall DAC25.2, iMod iPod, and Denon DP-59L/Clearaudio maestro.

I always listen at a calibrated (with pink noise) 80dBA for reviews - important for comparisons to have matched levels.

Also, my review loaner was a prototype, which is 100% representative of the final production except for the top case.

Performance:

In general, I thought the CONCERTO was a very impressive headphone amp. It has a very clean, highly transparent sound. The mids were very transparent and open, if just a tiny bit forgiving or sweet. Holly Cole’s voice on “The Train Song” was very cleanly rendered, and had good body, but was not thrust forward in the mix the way some amps do – a positive for the Meier in my book.

The treble was extended and nicely detailed, and perhaps just a tiny bit on the lively side. The incredibly wide variety of instruments in Steely Dan’s “Aja” were really well delineated. The Concerto is clear as a bell and clean as a whistle. I have always felt Meier amps excelled at being transparent – and the Concerto is no exception – it excels in this regard. The amp is just a touch on the lively side in the treble, but not significantly, and the treble was so clean that this was never an issue.

Detail retrieval was terrific. The sound of the guitar strings on the acoustic version of "Normal" from Porcupine Tree's "We Lost the Skyline" was very, very detailed, and in a natural, unforced way. I was really drawn into this performance by the Concerto - T1 combo - highly involving.

The deep bass was impressive – it had great weight, nice control, and impressive depth. The deep bass in “TeakBois” from Anderson/Bruford/Wakeman/Howe’s self-titled LP was very impressive. The Concerto drove the T1 down VERY deep – an area where T1 can really go. Double-bass from goth-metal like on Sirenia’s “The Seventh Summer” from “The 13th Floor” was really impressive. There is nothing enhanced here, but bass is ruler-flat, iron-fisted, and has no overhang.

The soundstage was very well defined, being both wide and deep. Lateral image stability was very, very good. Dynamics and speed were also very good. The Concerto dealt well with complex music like Aghora’s “Fade” from their record “Formless”, which alternates tempo numerous times, and features both very sparse and very dense segments – the Concerto handled the shifts here with aplomb. I went back and forth on using crossfeed - I liked it on some recordings, preferred it off on some, and on others couldn't really discern a difference. But since it's defeatable, it's nice to have it.

Other Players:

Overall, I thought the CONCERTO held its own very well versus its main competitor that I used for comparison’s sake, the Audio GD Phoenix – which is both much more full-featured, and more expensive, but is the only other SS amp I had on hand. I prefer not to compare SS amps just to tube amps, because while they are not as different sounding as some people think, there are differences. So the Phoenix was the main comparison point, although it does cost 60% more than the Concerto. The whole point of the Concerto is that it is a Meier Symphony with less features.

The comparison between them was fascinating, though. I have always thought of the Phoenix as being on the slightly dark and smooth side. And traditionally, I have actually felt the same way about most Meier amps I have heard. The Concerto, on the other hand, was a little lighter and brighter than the Phoenix – but I would still describe the Concerto as being very neutral and smooth. The difference between them was immediately noticeable, though. As such, I slightly preferred the Concerto with the JVC DX1000, but thought the Phoenix was better with the DT880 and HE-5. So this may give some idea about where the Concerto is most at home. It’s essentially neutral, but I would not describe the treble as soft or forgiving – clean, but present. So I wouldn’t get the Concerto for use with headphones that are prone to treble brightness themselves. While this is not a big deal or a defining character, it does represent a bit of a departure from Meier amps in the past, if memory serves me correctly.

The Beyerdynamic T1 was a tougher call. I liked it equally well though both, although the difference between the amps was most apparent with the T1. But the T1 sounded great with both. The 600 ohm T1’s did require the use of the Concerto’s high-gain mode, but it then drove them to very loud levels easily. Undeniably, the T1 used with the Concerto was wicked good, and shows that the Concerto can power the big boys and sound great. I would unhesitatingly recommend the T1 for use with the Concerto. I am enjoying that very combination as I write this.

Finale:

So in sum, I found the CONCERTO was nothing short of excellent and never anything less that very enjoyable. For $750, it’s a good value, IMO, considering its performance level. It is very basic in feature set, but is very well engineered, and the performance is at a very high level. For someone looking for a relatively compact, well built amp where the insides were more important than the outsides, it’s a great choice in a high-performance headphone amp. The Concerto reminded me just how good Meier Audio amps have historically been - and clearly still are. The Concerto offers about all the performance that anyone who isn’t spending VERY big bucks on a headphone amp, and who needs only one input and output, and only single-ended, could ask for. Definitely recommended.

Before having the LCD-2, I was mainly listening with the AKG K340 and Concerto combination. I still do, though less frequent now. For me this combination is very nice. Except for the treble which for me is a bit rolled off, the head-staging, vocals and imaging are very good while, with my pair of the K340, bass notes are clearly distinguishable and extended, and bass grunt or impact are delivered when the passages have them.

With the LCD-2/Concerto combination, it is a case of noticeably more, save for the head-staging, of what the K340/Concerto combination was delivering with better treble presentation plus transparency and details. With a revealing headphone like the LCD-2, I could easily hear the nuances and or inflections in the vocals, the shimmer of percussions and the fade of bass notes and drums. I believe this is only possible if and only if the whole chain is capable of details and is transparent (hmm, this is also saying quite a bit about the vintage Rotel RCD 965BX CD Player that I am using). Bass is significantly deeper, fuller and more impactful. This is telling me that the Concerto is certainly capable of driving current hungry low impedance headphones as well.

Does the Concerto roll off the treble? Certainly not, not for me. Listening with my SR 225, there is plenty of it, which is a characteristic of the SR 225. Again, this tells me that the Concerto is transparent. It does not add anything to the sound, or if it did, it is not noticeable.

Hence, for me, the Concerto is a very capable transparent headphone amp that is capable of driving and controlling not only current hungry low impedance but also mid/high impedance difficult to drive headphones. At least specifically, it mates very well with the AKG K340 and LCD-2.

Take the design of the SYMPHONY, remove the DAC section, add a few small improvements to the amplification circuitry and exchange the luxurious enclosure for a more modest and plain version and what you get is the upcoming CONCERTO.
Of course this amp has a built-in crossfeed filter and of course it also uses the concept of active balanced headphone ground. In addition the discrete (and technically very sophisticated) volume control now has 64 positions (32 positions for the SYMPHONY) which allows for very small stepsizes and a very analog feeling.
Technically the CONCERTO is an extremely advanced headphone amplifier and offers excellent value-for-money.